CVE-2019-15656 in DSL-2875AL
Summary
by MITRE
D-Link DSL-2875AL and DSL-2877AL devices through 1.00.05 are prone to information disclosure via a simple crafted request to index.asp on the web management server because of username_v and password_v variables.
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Analysis
by VulDB Data Team • 04/18/2024
The vulnerability identified as CVE-2019-15656 affects D-Link DSL-2875AL and DSL-2877AL broadband routers running firmware versions up to 1.00.05. This issue represents a critical information disclosure vulnerability that allows unauthenticated attackers to extract sensitive authentication credentials from the device's web management interface. The flaw exists within the index.asp web page handler of the router's embedded web server implementation, making it accessible to anyone who can reach the device's management interface over HTTP.
The technical root cause of this vulnerability lies in the improper handling of username_v and password_v variables within the index.asp script. These variables contain the administrative credentials in plain text format, which are exposed through a simple crafted HTTP request to the vulnerable web endpoint. The vulnerability stems from inadequate input validation and output sanitization practices within the web application layer of the router's firmware, where sensitive data is directly rendered without proper access controls or authentication checks. This type of vulnerability maps directly to CWE-200, which describes information exposure through improper output handling, and represents a classic example of insecure direct object reference where authentication credentials are exposed through predictable web paths.
The operational impact of this vulnerability is severe as it allows attackers to gain full administrative access to the affected routers without requiring any authentication credentials. Once exploited, the attacker can modify network configurations, change administrator passwords, install malicious firmware, or establish backdoor access points. The vulnerability affects not only the device's web management interface but also potentially compromises the entire network infrastructure that relies on these routers for connectivity and security policies. Network defenders face significant challenges since the vulnerability can be exploited remotely, and the affected devices may be located in environments where physical access is limited or impossible to monitor effectively.
Mitigation strategies for this vulnerability should include immediate firmware updates from D-Link to address the information disclosure issue, along with network segmentation to isolate these devices from critical infrastructure. Organizations should implement network monitoring to detect unusual traffic patterns that might indicate exploitation attempts, and consider disabling unnecessary web management interfaces when not actively required. The vulnerability also highlights the importance of secure coding practices and input validation within embedded web applications, aligning with ATT&CK technique T1566 which covers social engineering and credential access through web application vulnerabilities. Network security teams should also consider implementing web application firewalls to detect and block crafted requests targeting known vulnerable endpoints, and establish regular vulnerability assessment procedures to identify similar issues in other network devices.